Automatic electric cut-out



Dec. 27, 1927. 1,653,804

` A. E. HAGU E AUTOMATIC ELECTRIC CUT-OUT Filed Feb. 27. 1926 L 205A lj 2,74# I i y MM A@ Patented Dec. 27, 1927.V

UNITED STATES PATENT OFFICE.

ALFRED E. LEAGUE, OE EAST ORANGE, NEW iERsEYy AssIeNoR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OE NEW YORK, N. Y., A CORPORATION OF NEW YORK.

AUTOMATIC ELECTRIC CUT-OUT.

Appiicauon fried February 27, 1926. sei-iai No. mairie.`

This invention relates yto telephone exchange systems and more particularly to such systems wherein automatic switches are employed for establishing connections.

In electrical systems it is customary to Connect the battery supply to the apparatus under the control of current limiting devices such as'tuses which open the circuit in the `easel of an unusual increase in current due to any cause. In the case of machine switching telephone systems the apparatus constituting a switching unit is usually connected to battery through a single fuse. The blowing of such a fuse has long` been employed to cause an alarm to be sounded.V However, this alarm does not prevent the selection of the apparatus unit and the consequent Afailure of the attempted connection; .i

The object ot the present invention is the automatic removal of an apparatus unit trom service in response to unstandard conditions. A

A feature of the invention lies/in means responsive to such an overload as would operate a current limiting device to render busy the apparatus fed therethrough.

A more particular `feature of the invention lies in providing an extra winding on the relay which normally vrenders the apparatus unit busy, each terminal ot said winding being connected to battery through a separate current limiting device. v

It results `from the above arrangement that whenany part of the battery feed of an apparatus unit is overloaded, the relay mentioned isjoperated and locked to render the apparatus unit` busy until the batterv feed and current limiting .device have been restored to normal. Where the apparatus units are arranged serially, the unition which the overload occurs is automatically removed from the series and the control circuits extended to the next unit.

The arrangement of the invention may be applied to any type ot system but was particularly developed tor use in connection with an automatic private branch exchange ot the type disclosed inthe application ot W. P. Albert,` Serial No. 698,635, l led March 12,1924, patented April 13, 1926, No. 1,580,630.` It is of especial value in such a system since a private branch exchange would probably be dependent for maintenance on outside service and serious delays might result from the blowingot a. fuse.

The drawing shows the method of applying the invention to two types ot circuit. Ihe arrangement shown below the broken line is typical of a gang start arrangement; the arrangement shown above the b'rolren line is a slreletonized arrangement similar to that employed in the link and trunk circuits oit' the above identified applications.

An example ot the type of circuit shown below the broken line is the coin circuit disclosed in Fig. 13 of U. S. application of I. I'I. Henry, Serial No. 743,920, iiled October 16,

`192i, patented March 9, 1926No. 1,575,336.

Froma consideration of that application it will b e seen that, when one ot the coin circuits is to be employed, ground is connected `to the common start lead and over the back contact ot relay 1314 to the power magnet of the switch associated therewith. Similar circuits are completed for each idle coin circuit. When a coin circuitis associatedwith the selector circuit, relay 1314 is operated to stop the switch and remains Operated throughout the use of the coin circuit, thus rendering the circuit busy.

Itelays 1314-A, 1314-13, 13H-0, etc., shownin the drawing represent a relay, such as relay 1314 of the above mentioned application, individual to each of a number of coin circuits. The connection of ground to start lead 101 completes ay circuit (not completely shown) over the baclrcontact of each relay 1311i-A, 1314-Betcfor the power magnets ot the corresponding switches. The operation ot one of said relays prevents the completion of said circuit to the corresponding magnet. All the apparatus `of the switching unit associated with relay 131%A,.iior example, is fed through fuse 102: all that associated with relay 1314-13 is ied through fuse 103 and all that associated with relay 1314.-@ through fuse 104. An auxiliary winding is provided for each of these relays oneV side oi which is connected to battery` through the group ,tuses 102, 103, 104 etc. The other terminal 'of each winding is .also `connected to battery through a fuse.. To avoid the removing of the entire `number of apparatus unitsfrom service at one time, should the secondtermi-v lil nal of the relay be grounded, they are divided into two groups. The auxiliary winding olf all the relays of one group is connected to battery through fuse 105 and of all ol.t the other group through fuse 106.

v llhould any part of the battery feed conductor llQ be grounded directly, it would result in blowing fuse 102. This same ground would complete a circuit from hatf` tery over bus bai' 150 through fuse 105, left winding ot' relay 1mi-4A, to this ground. Relay lSlLlf-A when locked to ground through resistance 122 will remain locked un til the Iground has been removed and the fuse 102 replaced,v at which time the current through the left winding `is reduced suliiciently to permit the relay to release. The operation of relay 13H-A would open the circuitot the corresliionding power magnet and render the unit busy. The auxiliary winding is sullieiently marginal to be unafl'ected by operating` grounds through relays etc.

The operation in case an excessively high voltage were appliedto conductor 112 would he the saine. It battery or excessive voltage were applied to the special battery teed i', half oi' the units would be removed `from service.

The blowing ot any of the fuses releases a link (not shown) to connect bus bars 1.50 and 140. This link completes a circuit to ground through relay 141. Relay 141 in operating closes a circuit for lamp 142 and buzzer lfl, providing both a visual and an audible signal that a `fuse has been blown. One or both ol these signals may conveniently be located at the central office.

y i llie arrangement shown above the `broken line shows the application oi' the invention to the system disclosed in the above mentioned Albert application. Relay 9.01i'epresents `the line `relay ot that disclosure.

Relays 20o-dl, 205-43. 205-4), etc., represent the start relays of a plurality ot link circuits, Relays 20a-ul, 20s-B. 5204*@ ctc. represent the transfer relays ot the corresponding link circuits. It is obvious that the opeation of relay 201 will causethe op eratioiroi relay QOFi-A if .relay QM-A is not operated and that the operation of each of the relays "20k-A, 20a-*B or 20er-C transfers the start circuit controlled by re- `lay 201. to the start circuitof the next link circuit. From a consideration ot the above mentioned Albert application it will be seen that the relay 204: of the link circuit is op eralted as soon as the calling line has been connected through to that link circuit translerring the start circuit to the next link ciicuit. y

As in the case of relay `1314:-A, etc., relay 520i-lull has been 'provided with a second winding, one sident which is connected to batter7 through fuse 151, which fuse feeds battery to the apparatus of the corresponding link circuit, and the other side of which is connected to battery through fuse 154, which is common to one halt the relays 204-A, etc. Since battery potential is the same ou each side ol the winding. there will be no current drain therethrough. If the feed lead ot' any lilik circuit such as lead 156 .is grounded or crossed with a high voltage, the associated relay 20a-ll will be operated and` will lock through resistance 15T to ground, thus transferring the start circuit to the next link.

That the invention particularly advan tageous in an arrangement of this sort may be readily seen. `Suppose, for example, that relay o-A were, 'as slioivn.` the lirst relay to which the start lead is extended. lttuse 151 shouldlie blown. neither relay @U5-r nor relayQOfl-A could operate and the entire system would be out ot service until the fuse replaced.

The operation et the alarm circuit 145 would be the same in thiscase as above described.

V'Vhat is claimed is:

y l. In a telephone exchange system` a plurality of switches.` means in each switch lor normally rendering said switch busy, separate means tor supplying the apparatus` ol each switch withbattery, and means responsive toan unstandard condition of said battery supply means to operate said busying means. ,y

2. In a telephone exchange system, a plurality` ot switching units. means supplying battery to the apparatus ot' a switching unit under the control of a current limiting de vice responsive to an uustandard condition ot said battery supply means, and means also responsive to an unstandard condition oi said battery supply mearis to remove said switching unit from service.

3. In a telephone exchange system. a plurality of switching units, means in each switching unit for normally rendering said switching unit busy, means for supplying the apparatus of each switching unit with battery under the control of a current limitl ing device responsive to `an unstandard condition of said battery supply means and means also responsive to animstandard coudition ot said battery supply means to operate said busying means.

4l. In a telephone exchange system, a plurality o't switching units, means in each of said switching units `iiicliuling a relay for normally rendering said switching unit busy, means 'tor supplying the apparatus of each switching unit with battery under the control of acurrent limiting device individual to said unit and responsive to an unstandard condition oi said battery supply means, an auxiliary winding for said busying relay, and means also eiective in the presence of an unstandard condition to energize said relay through said auxiliary winding.

5. In a telephone exchange system, a plurality7 of switching unit-s, means for Supplying battery to the apparatus of each switching unit under the control of a current limiting device, and means responsive to the presence of an unstandard condition which would operate said current limiting device to also remove said switching unit from service.

6. In a telephone exchange system, a plurality oi' switching units, means in each switching unit for normally rendering said switching unit busy, means for supplying the apparatus of each switching unit with battery under the control of a current limiting device individual to said unit, and means responsive tothe presence of an unstandard condition which would operate said current limiting device to operate said busying means.

7. In a telephone exchange system, a plurality of switching units, means for supply-- ing battery to the apparatus in each switching unit through a fuse, and means for employing an unstandard condition that would open said fuse to removed said switching unit from service.

8. In a telephone exchange system, a plurality of switching units, means in each switching unit for normally rendering said switching unit busy, means for supplying the apparatus of each switching unit with battery through a fuse individual to said unit, and means responsive to the presence of an unstandard condition which would open said fuse to operate said busying means.

9. In a telephone exchange system, a plurality of switching units, means in each oit said switching units including a relay for normally rendering said switching units busy, means for supplying the apparatus oi' each switching unit with battery through a fuse individual to said unit, and means responsive to the presence of an unstandard condition which would open said fuse to operate said busying relay.

l0. In a. telephone exchange system, a plurality of switching units, means in each of said switching units including a relay for normally rendering said switching unit busy, means for supplying the apparatus of each switching unit with battery through a fuse individual to said unit, an auxiliary winding for said busying relay, and means responsive to the presence of an unstandard condition which would open the fuse to energize said relay through said auxiliary winding.

11. In a telephone exchange system, a plurality of Switching units, means in each of said switching units including a relay for normally rendering said switching unit busy, means for supplying the apparatus of each switching unit with battery through al fuse individual to said unit, an auxiliary winding for said busying relay, means responsive to the presence of an unstandard condition which would open said fuse to energize said relay through. said auxiliary winding, and means to hold said relay operated until said unstandard condition has been removed.

l2. In a telephone exchange system, a plurality of switching units, means in each of said switching units including a relay for normally rendering said switching unit busy, means for supplying the apparatus of each switching unit with battery through a fuse individual to said unit, an auxiliary winding on said busying relay each terminal of which is connected to battery through a separate fuse whereby the presence of an unstandard condition which would open said fuse will energize said relay through said auxiliary winding to render said switching unitbusy.

13. In a telephone exchange system, a plurality ot switching units, means in each of said switching units including a relay for normally rendering said switching unit busy, means for supplying the apparatus o each switching unit with battery through a inse individual to said unit, an auxiliar winding on said busying relay each term1- nal of which is connected to battery through a separate fuse whereby the presence of an unstandard condition which would open said fuse will energize said relay through said auxiliary winding to render said switching unit busy, and means to hold said relay operated until said unstandard condition has been removed.

In witness whereof, I hereunto subscribe my name this 26th day of February A. D.,

ALFRED E. HAGUE. 

